Electric clutch and brake controlled press



March 3, 1953 M. P. wlNTHER ELECTRIC CLUTCH AND BRAKE CCNTRCLLED RREss Filed oct. 21, 1946 BRAKE c BRAKE 270 MECHANICAL V ELECT 2E? ELECTRIC COUPLI, NG

SINGLE CYCLE March 3, 1953 M. P. wxN'rHER 253303167 ELECTRIC CLUTCH AND BRAKE CONT-ROLLE!) PRESS FIGB.

March 3, 1953 M. P. WINTHER ELECTRIC CLUTCH AND BRAKE CONTROLLED PRESS Filed oct. 21, 194e 3 Sheets-Sheet 3 FIGB.

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Patented Mar. 3, -1953 ELECTRIC CLUTCH AND BRAKE CONTR-OLLED PRESS Martin P. Winther, Waukegan, Ill., assigner, by mesne assignments, to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application October 21, 1946, Serial No. 704,552

24 Claims. (Cl. 172284) This invention relates to presses and, with regard to certain more specific features, to punch presses for punching or forming operations.

Among the several objects of the invention may be noted the provision of a high-speed, high-capacity, light-weight press in which impact stresses are minimized; the provision of a press of the class described which operates smoothly at high speeds to store energy in a ywheel and transfer it to the ram of the press; the provision of a press of this class which may readily be selectively operated to run through one full-stroke operating cycle and stop, or to run continuously, or to creep in either direction; and the provision of such a press which is simple and strong in construction and inexpensive and safe to operate and maintain. Other objects will be in part apparent and in part pointed out hereinafter.4

The invention accordingly comprises the clements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

Fig. 1 is a simplified, diagrammatic, skeleton layout of the press of this invention, its crank being shown at and its ram being shown at the beginning of a work movement;

Fig. 2 is an enlarged longitudinal section through a flywheel, slip coupling and brake assembly, shown diagrammatically in Fig. 1;

Fig. 3 is an electrical circuit diagram;

Fig. 4 is a developed diagrammatic view of a lgroup of cam-operated switches associated with .the press; and

Fig. 5 is a developed diagrammatic View of a Vmaster selector switch.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now more particularly to Fig. 1, there is shown at the slide or ram of a press, which may be a punch press for punching or forming metal or the like. The ram is linked by a connecting rod 3 to the crank or eccentric 5 of a crankshaft or ram shaft 1. The crankshaft is driven from a drive shaft 9 through speedreducing gears Il and I3. The drive shaft 9 is adapted to be rotated by a motor I5 through an electromagnetic eddy-current slip coupling l1. This coupling includes a driving eld rotor i3 and a driven inductor member 2l. It is sometimes referred to herein as an electromagnetic slip coupling or magnetic flux clutch. The field rotor is formed as a pulley and is driven by V-belts 23 from a pulley 25 on the shaft of motor I5. The iield rotor is mounted upon a flywheel 21, which is rotary on the end of drive shaft 9. The inductor member 2| is adapted to be braked electromagnetically by a stationary braking eld member 29. The combination of members 2| and 29 may be referred to as an electromagnetic brake or dynamic iux brake. This brakes the drive and crankshafts. The crankshaft is also under the control of an electromechanical brake 3l and is coupled by a 1:1 ratio chain and sprocket drive 33 to the camshaft 35 of a group of cam-operated switches 31, 39, 4I, 43 and 45, the function of which will be described subsequently. The electromechanical brake 3l is of the usual variety which is set by a spring 30 when its solenoid coil G is deenergized. When the coil G is energized the brake is drawn open to release position against the action of its spring. It may be referred to as a mechanical brake or mechanical solenoid brake.

Details of the iiywheel, electromagnetic clutch and electromagnetic brake assemblies are shown in Fig. 2. As illustrated, flywheel 21 has la hub 41 journalled by roller bearings 49 on the end of the drive shaft. The field rotor I9 4includes a hollow ring-like structure secured to the flywheel by screws 5I and formed with peripheral grooves 53 to receive the belts 23. Within the hollow ring-like structure are two annular eld coil-s 55. The ring structure is formed internally with a series of peripherally spaced, and axially lapped magnetic pole teeth 51 which are broadly similar to those described in my U. S. Patent 2,367,636, dated January 16, 1945. The field coils 55 are energized from wires 59 and 6I through a slipring connection 63. When energized, the coils induce magnetic lpoles in the pole teeth 51 of the field rotor. These poles extend radi-ally inward.

The inductor member 2| comprises a smooth, magnetic, eddy-current inductor ring fixed on a hub 61 which is keyed to the drive shaft 9, as indicated at 69. Two copper end rings 1I and 13 are attached to the ring 65 to reduce the resistance to flow of eddy currents therein. When the eld coils 55 of rotor I9 are energized and the rotor driven by motor I 5, the inductor member 65 has eddy currents engendered therein and becomes -driven by magnetic reaction. This rotates drive shaft 9. The degree of coupling is a function of the excitation of coils 55.

The braking eld member 29 comprises a hollow ring structure 15 secured by screws 19 to the press frame Tl. This ring structure, disposed within the inductor ring 65, is formed with alternate oppositely directed pole teeth 8| similar to teeth 5l above mentioned, except -that they eX- tend o-utward towards the inside of the inductor 65, instead of inward. An annular eld coil 83 disposed in the hollow ring structure is adapted to be energized by wires 85 Iand 07|. When energized, coil 03 induces magnetic poles in pole teeth 8| to brake the inductively related indu-ctor member 2| by magnetic reaction, according to the excitation of coil 83.

It will be clear from the above description that when the motor I5 is energized to drive the eld rotor I9 and ilywheel 2l, .and the coils 55 are energized, the drive shaft 9 will be driven through the slip coupling and drive crankshaft 'i to reciprocate the ram. When coils 55 are deenergized, and the coil 83 of the braking field is energized, the drive shaft will be braked to stop rotation of the crankshaft and hence t0 stop the ram.

The invention includes means whereby the operator may readily selectively control the press, through control of the motor I 5, the electromagnetic clutch and brake and the mechanical brake 3|, to run through one full stroke or cycle of the ram (one revolution of crankshaft 7) and then automatically stop, or t-o cycle continuously without stopping between cycles, or to inch, which means to creep by small increments through any portion of a cycle in either direction. This selective control is effected by means of a master selector drum-type switch S, which is shown in diagrammatically `developed form in Fig. 5. `This switch includes seven pairs of contacts S-I to S-I adapted to be bridged by contactor bars on a drum S movable t-o any one of four positions. In one position, designated Open, all contact-s are open. In another position, designated Single Cycle, contacts S-I, S-2 and S-3 are closed. This conditions the press for operation through one full-stroke cycle and then to stop. In another position, designated Continuous, contacts S-I, S-Z, S-ll and S-5 are closed. This conditions the press to operate continuously without stopping between cycles. In the last position, designated Inch, contacts only S-t and S-'I are closed. This conditions the press to creep at slow speed through any part of a cycle. The manner in which such control is yeifected will be developed 4in due course.

As illustrated in Fig. 3, the motor I5 is energized by a three phase power line including wires 9|, 93 and 95, a line switch 99 being included in the circuit. AV motor control circuit I is connected across one phase of the power line designated by wires 93 and 95. This circuit includes a relay coil A, momentary push butt-on mak-eand-break switches 97 and 99, respectively, and a shunt circuit around switch 9i including contacts A-I. Contacts A-I, and also contacts A-2, A-3 and A-l in wires 9|, 93 and 95, respectively, are grouped for simultaneous operation by relay coil A. When the coil is energized by pressing push button switch 91, it operates to close all yof contacts A-I, A-Z, A-S and A-ll. This completes all phases of the circuit to motor I and establishes a holding circuit through closed contacts A-I in shunt circuit I 0I to maintain coil A energized even though the push button switch 97| is released. The motor may be deenergized by momentarily pushing switch 99, which breaks the motor control circuit and de- 'energizes relay coil A to open contacts A-I, A-2, A-3 and A-4. A reversing switch |02 is provided in phase 9|, 93 of the power supply so that the direction of rotation of motor |5 may be reversed when desired.

Power is derived from the three-phase power supply to energize a control circuit II and a rectifier circuit III, the latter circuit supplying rectiied current to the field coils 55 and 83 of the field rotor I9 and braking field member 29, respectively.

The control circuit II includes a plurality of relay coils B, C, D, E, F, G and H, each of which controls certain contacts associated therewith in a manner to be described. Power for energizing these relay coils is derived from the secondary of a step-down transformer |03, the primary of which is in a line |05 connected across one phase iii, 93 of the three phase power supply. The secondary of transformer I 03 feeds wires |01 and |09.

The relay coil B when energized closes contacts B-I, B-2, B-3 and B-II associated therewith for group operation. This coil is connected across wires |01 and |09 in a line III including a normally closed push button break switch H3, contacts S-I of the master selector switch S (Fig. 5), two control switches I I5 and I I1, and contacts S-Z of the master selector switch S. The control switches I|5 and |I`| are each double-pole push button switches, biased so that their upper contacts normally are closed in line III. When contacts S-I and S-Z are closed, a circuit is completed from wire |01 through relay coil B to wire |09 through the upper contacts of control switches H5 and II?. A line IIS Shunted around control switch ||5 includes a cam-operated switch 3l and contacts B-I. A line |2| shunted around control switch II'I includes a cam-operated switch 45 and contacts B-ll. When coil B is energized, contacts B-I and B-A are closed and these shunts function as holding circuits ioi coil B as long as cam-operated switches 3? and 139 are closed, and the switches H5 and II'! may be operated without deenergizing coil B.

The relay coil C` when energized closes contacts C-I, C-2, C-3 and C-4 associated therewith for group operation. This coil C is connected in parallel with coil B in a line |29 including the lower contacts of control switches IIE and II'I' and also the contacts B-2 and B-S. When control switches 5 and I|'| are pressed (contacts S-I and `S-Z being closed), the circuit through coil C is completed through the lower contacts `of switches I I5 and I The relay coil D is connected in a parallel circuit with coil C and becomes energized when coil C is energized and closes all of contacts C-I, C-Z, C-3 and C-4. Coil D is also connected in a line I 24 across wires |01 and |09 including the push button switch ||3, contacts S-t, the upper contacts of a two-pole push button inching control switch |25 and contacts S-l. The coil D when energized closes contact D-I in the con- III and controls the energization of the braking field coil 83.

The relay coil F is connected in a shunt circuit I3I around coil D and is energized whenever coil D is energized. Coil F controls contacts F-l. This pair of contacts is normally closed and opens when coil F is energized.

The relay coil G is connected across the shunt circuit |3| in a line including contacts D-I. This coil is energized when coil D is energized since contacts D-I are closed under such conditions. Coil G is a control solenoid for the mechanical brake 3 I. When the coil G is energized, brake 3| is released. The arrangement whereby the coil releases the brake is of any suitable conventional solenoid form such as shown in the lower portion of Fig. 1 and above described.

The relay coil H is connected in a line |33 across wires |01 and |09 including the lower contacts of the inching control switch |25. This coil when energized closes speed-control contacts H-I in the rectifier circuit III.

The cam-operated switch 39 is connected in a line |34 adapted to shunt the bottom contacts of the control switch I I when switch 39 is closed. Similarly, the cam-operated switch 43 is connected in a line |36 adapted to shunt the bottom contacts of the control switch I|1 when switch 43 is closed. The contacts S-4 of the master selector switch are connected in a line |38 adapted to shunt the switch 39 when the contacts S-4 are closed. Similarly, the contacts S-5 are connected in a line |40 adapted to shunt the switch 43 when the contacts S-5 are closed.

.As illustrated in the development of Fig. 4, the cams for the cam-operated switches 31 to 45 are so designed and phased as to open switches 39 and 43 for the iirst 182 of the cycle of the crankshaft 1 and the press ram, to close these switches over the portion of the cycle between 182 and 245 and to open the switches from 245 to 360. Switches 31 and 45 are closed by their cams for the rst 225 of the press cycle, opened from 225 to 270, and closed from 270 to 350. Switch 4| is open for the first 195 of the press cycle, and closed for the remainder. The purpose for such timing will be made clear subsequently.

The rectifier circuit III derives power from the secondary of a transformer I4| the primary of which is connected in a line |43 across the phase 9| 93 of the three phase power supply. Included in line |43 are contacts D-2, a resistance |45, the primary of the transformer, and contacts D-3. A shunt |41 around contacts D-2 includes contacts E-I. A shunt |49 around contacts D-3 includes contacts E2. A shunt |5I around the resistance |45 includes the contacts H-l.

The rectifier circuit includes a pair of gas-filled diodes |53 and |55. The anodes of these tubes are connected to the secondary of transformer |4| The cathodes of these tubes are in a heater circuit |51 energized from the secondary of a transformer |59. The primary of transformer |59 is in a line |5| connected across phase 9|, 93 of the three phase power supply and including a rheostat |63 whereby the heater current of the cathodes may be varied. When the circuit through line |43 is completed, the transformer I4| is energized and its secondary impresses a voltage on the anode of diode |53 that is 180 out of phase with the voltage impressed on the anode of diode |55. The rectified output of the diodes is supplied to lines |65 and |61 connected to taps of the secondaries of transformers |4| 6 and I 59, respectively. These lines are adapted to supply the eld coils 55 and field coil 83.

The field coils 55 are connected in series across lines |65 and |61 in a circuit including contacts D4, a resistance |69, wire 59, coils 55 and wire 6|. The coils 55 are protected from inductive kick by a thyrite resistor I1| in a shunt around the coils. The contacts D4 are protected from overload and arcing by a condenser |13 and fuse |15 in a shunt around the contacts.

The braking field coil 83 is connected across lines |65 and |61 in a circuit including contacts E-3, wire 85, coil 83 and wire 81. The coil is protected from inductive kick by a thyrite resistor I 11 in a shunt around the coil. The contacts E-3 are protected from overload and arcing by a condenser |19 and a fuse |8| in a shunt around the contacts.

Operation is as follows:

To operate the press for a single cycle (one reciprocation of the press ram and return), the master selector switch S is set in the Single Cycle position wherein contacts S-l, S-Z and S 3 are closed. Line switch 9S being closed, the push button switch 91 is pressed to energize motor |5 and drive the field rotor I9. At the start of a cycle cam-operated switches 31 and 45 are closed, and 39, 4| and 43 are open. With contacts S-I and S-2 closed and control switches I|5 and |I1 in normal position, the circuit through line II| including coil B is complete. Coil B, being energized, closes contacts B|, B-2, B-3 and B-4. With contacts S-I and S-2 and contacts B-I and B-4 thus closed, the holding circuits I|9 and |2| around control switches |I5 and |I1 are completed to maintain coil B energized.

To start the cycling of the press, the operator presses control switches ||5 and I|1 simultaneously. These control switches are so located that the operator must, as a safety measure, use one hand on one switch and the other hand on the other switch, with both hands remote from the press ram. This closes the bottom contacts of control switches I|5 and I|1 and completes a circuit through line |23 and coil C, contacts B-2 and B-3 in this line now being closed. Energization of coil C closes contacts C-l, C-2, C'3 and C-4 and energizes coils D, G and F, as previously described. Coil G then releases the mechanical brake 3| to permit the crankshaft 1 to rotate. Coil D closes contacts D-2 and D=3 to complete the circuit of the primary of transformer I4| to provide rectified current for the eld coils 55. At the same time, coil D closes contacts D4 to complete the circuit through the field coils 55. Coil F opens contacts F-I to deenergize coil E (switch 4I being open). Coil H is energized to close contacts H-l and shunt out resistance |45.

With the coils 55 of field rotor I9 energized as above described, the press is driven from the inotor I5 and flywheel 21 through the slip coupling |1 to perform the punching, forming or the like operation. The crankshaft 1 rotates camshaft 33 at a 1:1 ratio. The operator retains control switches II5 and ||1 pressed in to keep their bottom contacts closed until the press has cycled at least through 182 and the ram has started its upward stroke. At 182, cam-operated switches 39 and 43 close (see Fig. 4). The operator may now release control switches ||5 and ||1. This opens their bottom contacts, but switches 39 and 43, being closed, provide a shunt circuit to maintain coil C energized. This maintains coil D energized to keep its associated contacts D-I, D-2,

7 D- and D-4 closed and-maintain field coils 55 energized so that the clutch continues to drive the press.

When the press has cycled through 195, camoperated switch 4l closes (Fig. 4). This confipletes the circuit through coil E in line I2?, con tacts S-3 being closed. Coil E then closes contacts E-l, E Z and E-3. The circuit of the primary of transformer I4| is completed through E-l and E-Z as long as coil E is energized. Closure of contacts E-3 completes the circuit through the braking field coil 83 and energizes the braking iield member 29 to exert a braking action on inductor member 2|.

When the press has cycled through 245, camoperated switches 39 and 43 open (Fig. 4). This breaks 'the circuit of coil C and each of coils C, D, F and G is deenergized. Deenergization of coil D opens contacts D-I, D-2, D-.Ei and D-ll. Opening of contacts D-4 breaks the circuit of the field coils 55. This deenergizes the electromagnetic clutch and no further driving torque is exerted on the press. Deenergization of coil F closes contacts F-l to complete the circuit through coil E to close contacts E3 and energize the braking eld coil 83. Deenergization of coil G applies the electromechanical brake 3l. The combined braking action brings the press to a stop after it has cycled through the remaining 115 to its initial position at 0.

Thus, the control functions to release both the electromagnetic brake and the mechanical brake and to energize the slip coupling at the start oi the cycle. The slip coupling exerts torque to drive the press over 2457 of its cycle.

The electromagnetic brake is applied, however. at 195, just after the ram passes mid-stroke, i. e., at the completion of the work movement. Thus, over the 50 of the cycle from 195 to 245 both the electromagnetic clutch and brake are operative. This allows the electromagnetic brake to attain a strong braking eiTort just as the clutch is released, thus assuring complete control. At 245 the clutch is cut out, the electromagnetic brake remains applied, and the mechanical brake is also applied. These brakes ibring the press to a denite stop quite close to the end of the cycle at The electromagnetic brake inherently cannot exert any substantial braking effort at low speeds of the inductor mem ber, as the crankshaft 'E nears the end of the cycle, since braking torque depends upon substantial slip, but the mechanical brake functions completely to stop the press at its initial position.

If the operator should fail to release the con trol switches H and lil, the press is prevented from repeating thecycle by the action of carnoperated switches 3T and 45. These switches open at 225 to break the holding circuits il@ and l2! for the relay coil B (Fig. 4). if switches H5 and lll are pressed down at this time, their upper contacts are open and coil B is deenergized. This opens contacts B-I, B-Z, B-Z-B and B-e, deenergizing coils C, D, G and F. As previously described, deenergization of these coils deenergizes the slip coupling, energizes the electromagnetic brake and applies the mechanical brake to bring the press to a stop. A cycle cannot be repeated until the operator releases both control switches H5 and Il'l and then reapplies them.

To operate the press continuously, without automatic stopping between cycles, the master selector switch S is set in the Continuous position' wherein contacts S-l, S-2, S-e and S-E are closed. Closure of contacts S-l and S-2 com,e pletes the circuit through relay coil B and closes contacts B4, B-2, B-3 and Beft as previously described. To start continuous operation of the press, the operator presses in control switches i i5 and Ill to close their bottom contacts. This energizes relay coil C (contacts S-i, B-2, B3 and S-2 being closed) and closes contacts C-I, C-Z, C-3 and C-4. Closure of 'these contacts energizes coils D, G and F to energize the rotor eld coils 55, release the mechanical brake 3l and deenergize braking eld coil 83 in the manner previously described. The press is then driven through the energized slip coupling i'i.

The operator retains control switches H5 and Ill pressed in until the press cornes up to speed, and may then release the switches. In this case an automatic press feed may be used. Even though switches H5 and Iii are released and their bottom contacts are open, coil C re mains energized through the shunt circuits 138 and Mi] including the contacts S-i and S-5, which are always closed during continuous operation. The cam-operated switches 3l', t5 and 39, and i3 have no eiect on coil. C since all of these switches are shunted by the shunt circuits E38 and Util. Cam-operated switch al has no eiiect during continuous operation since contacts S--t are open (Fig. 5). The press` continues to cycle until the break switch H3 is pressed to break the circuit to coil C. Thus, during continuous operation of the press, the slip coupling l? is continuously energized. The mechanical brake 3i is released and braking eld coil 83 is deenergized so that there is no braking of the crankw shaft i.

To operate the press at very slow creeping speed through a portion of the stroke of the ram, the master selector switch is set in the inch position wherein contacts S-i and S-E are closed (Fig. 5). The operator then presses in the inching control switch 125. This completes a circuit from line le? to line [69 through line l2i including switch H3, contacts S-, the upper contacts of switch 25, relay coil D and contacts S-l. 1t breaks the circuit of relay coil H by opening the bottom contacts of switch E in line i355. Energization of coil D energizes coils G and F and releases the mechanical brake and deenergizes the braking field coil 83 in the manner previously described. It also closes contacts De?, D-3 and D i to energize rotor eld coils 55 and energize the slipv coupling il to drive the press. Since relay coil H is deenergized, however, contacts H-l are open. Thus, resistance M5 is in series with the primary of transformer M i, thereby to reduce the voltage output of the rectiiier circuit. The result is that the energization level of rotor held coils is low and the slip coupling i? drives the drive shaft 9 with considerable slip so that the press is driven slowly. The press is driven as long as switch E25 is pressed in. To reverse the direction of movement of the ram it is merely necessary to reverse the direction of rotation of r motor l5 by means of reversing switch |52. This inching operation is not intended for power punching or forming but for fine adjustments or the ram l required for setting and aligning dies and the like.

Reduction of the output of the rectiiier cir* cuit lll due to insertion of the resistance M5 causes a reduction in torque delivered by the electromagnetic clutch, as well as reducing its speed. This torque reduction is suflicient to pull the mechanism through the inching work for 9 so-called inching, but it offers protection against shearing or destroying a misplaced die, since the torque is not great enough to cause breakage.

Thus, by suitable setting of the master selector switch S, the press may be operated by means of control switches I| to Il1 to run through one full stroke and stop; or to run continuously, or to inch in either direction. Energy is stored in the flywheel 21 when slip coupling i1 is deenergized or when there is no load on the press and this energy is transferred smoothly and effectively to the ram when the slip coupling is energized. The smooth action of the electromagnetic eddy-cui'- rent coupling minimizes impact stresses and permits operation of the press at high speeds and high capacities. The coupling and electromagnetic brake have no frictionally engaged surfaces subject to wear and consequently the press is inexpensive to maintain.

It will be observed that while the cams i5-ll are timed in respect to one revolution of the crankshaft l, the speed-reduction gears ii, i3 effect several revolutions of the drive shaft il for one revolution of the crankshaft l. This calls for the desirably higher slip speeds of the inductive coupling and of the inductive brake for eicient operation of these. Thus the operating torques of the coupling and of the brake are higher for a given speed of the crankshaft l than if these units were connected in a 1:1 ratio with the crankshaft l. It should also be observed that the life of inductive slip couplings and brakes is not shortened by high slip speeds. On the other hand, the mechanical brake 3| is associated directly with the crankshaft 1, which is desirable, since in such a brake reduction of slip speed prolongs its life. Another advantage of having the inductive slip coupling and inductive brake operative on the shaft 9 is that their torque effects on the crankshaft 'I are multiplied through the speed-reduction gears Il, I3.

It will be understood that, while the field rotor is illustrated as the driving member of the slip coupling and inductor member as the driven member, this relation may be reversed. It will also be understood that suitable time delay means may be employed to prevent plate voltage from being applied to diodes |53 and |55 until their cathodes have heated sufficiently. Also, a time delay means may be incorporated in the control circuit to deenergize relay coil E after a predetermined interval to open contacts 113-3 and deenergize braking field coil 83. This is to prevent unduly prolonged energization of the electromagnetic brake. These items are not illustrated for the reasons that (l) their applications are common knowledge, and (2) a showing of them would unduly obscure the disclosure of what is considered to be new herein.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

l. In a press, a ram shaft, a drive shaft, a speed-reduction connection between the drive shaft and the ram shaft, a substantially constantly moving flywheel, an inductive electric slip coupling between the flywheel and the drive shaft, an inductive electromagnetic brake operative directly on the drive shaft at drive shaft speeds, a mechanical brake operative directly on the ram shaft at ram shaft speeds, and means for automatically controlling the sequence of operations of said electric coupling, electric brake and mechanical brake, whereby during one revoluton of the ram shaft the electric coupling is rst applied and then released after one-half revolution, then the electric brake is applied before said coupling is released and the mechanical brake is applied during the period after the inductive coupling is released.

2. In a press, a ram shaft, a drive shaft, a speed-reduction connection between the drive shaft and the ram shaft, a substantially constantly moving iiywheel, an inductive electric slip coupling between the iiywheel and the drive shaft, an inductive electromagnetic brake operative directly on the drive shaft at drive shaft speeds, a mechanical brake operative directly on the ram shaft at ram shaft speeds, and means for automatically controlling the sequence of operations of said electric coupling, electric brake and mechanical brake, whereby during one revolut1on or the ram shaft the electric coupling is first applied and then released after one-half revolution, then the electric brake is applied before said coupling is released and the mecnanical brake is applied during the period after the inductive coupling is relased, and before tne electric brake is released.

3. A press comprising a rain, means for actuating the ram through complete strokes including a rotary shaft, means for driving the shaft includlng an electromagnetic slip coupling, said coupling including relatively rotatable iield and inductor members, one of said coupling members being coupled to said shaft, said field member including a field coil, manually controlled means for energizing said held coll to apply torque through said coupling to said shaft to reciprocate the ram, and means operating in timed relation to said ram for automatically deenergizing said field coil after the ram has passed mid-stroke.

4. A press comprising a ram, means for reciprocating the ram including a rotary shaft, means for driving the shaft including an electromagnetic slip coupling, said coupling including relatively rotatable field and inductor members, one of said coupling members being coupled to said shaft, .said coupling iield member including a field coil, a braking eld member having a field coil and being in inductive relation to said one coupling member, manually controlled means for energizing said coupling field coil to apply torque through said coupling to said shaft to reciprocate the ram, and means operating in timed relation to said ram for automatically energizing said braking held coil after the ram has passed midstroke and subsequently deenergizing said coupling eld coil.

5. A press comprising a ram, means for reciprocating the ram including a rotary shaft, means for driving the shaft including an electromagnetic slip coupling, said coupling including relatively rotatable field and inductor members, one of said coupling members being coupled to said shaft, said coupling lield member having a field coil, a braking field member having a field coil and being in inductive relation to said one coupling member, a mechanical brake for said ram, manually controlled means for energizing said coupling field coil to apply torque through said coupling to said shaft to reciprocate the ram,

11 and means operating in timed relation to said ram for automatically energizing said braking field coil after the ram has passed mid-stroke and subsequently deenergizing said coupling field coil and applying the mechanical brake.

6. A press comprising a ram, means for reciprocating the ram including a rotary shaft, means for driving the shaft including an electromagnetic slip coupling, said coupling including relatively rotatable field and inductor members, one of said coupling members being coupled to drive the shaft, said coupling field member including a field coil, a control circuit including manually controlled means for energizing said field coil to apply torque through said coupling to lsaid shaft to reciprocate the ram, means operating in timed relation to said ram for automatically d'eenergizing said field coil after the ram has passed mid-stroke, and selector means for selectively connecting said timed means in said circuit for single-stroke operation of the ram or for shunting said timed means out of said circuit for continuous operation of the ram.

'7. A press comprising a ram, means for reciprocating lthe rain including a rotary shaft, means for driving jthe shaft including an electromagnetic slip coupling, said coupling including relatively rotatable field and inductor members, one of said coupling members vbeing coupled to drive the shaft, said coupling field member including a 'eld coil, `a braking field Vmember having a field coil and being in 'inductive relation to said one coupling member, a control circuit including manually controlled means for energizing said coupling field coil to apply torque' through said coupling vto said shaft to reciprocate the ram, means operating Yin timed relation to said ram for automatically energizing said braking field coil'after the ram has passed midstroke and subsequently deenergizing said coupling field coil, and selector means'for selectively connecting rsaid timed means in said circuits for single-stroke operation of the ram or for shunting said timed'means out of said circuit for continuous operation of the'ram.

v8. A press comprising a ram, means for reciprocating the Vram including a rotary shaft,

means for driving the shaft including an electro- 4mag'neticslip coupling, said coupling including relatively rotatable held and inductor members,

one of said couplingmembers vbeing coupled to drive the shaft, Ysaid coupling field member including a field coil, a braking field member having a field coil and being in inductive relation to said one coupling member, a mechanical brake for said ram, a control circuit including manually controlledV means for energizing said coupling field coil to apply torque through said coupling to said shaft to reciprocate the ram, means operating in timed relation to said ram for automatically energizing said braking field coil after the ram has passed mid-stroke and subsequently deenergizing said coupling field coil and applying the mechanical brake, and selector means for selectively connecting said timed means in said circuit for single-stroke operation of the ram or for shunting said timed means out of said circuit for continuous operation of the ram.

9. A press comprising a ram, means for reciprocating the ram including a rotary shaft, .means for driving the shaft including an electromagnetic slip coupling, said coupling including relatively rotatable iield and inductor members, one of said coupling members being coupled to drive the shaftf'said coupling field member including a eld coil, a control circuit including manually controlled means for energizing said field coil to apply high torque through said coupling to said shaft to reciprocate the ram at relatively high speed, said circuit also including inching contro1 means for energizing said field coil to apply low torque through said coupling to said shaft to reciprocate the ram at inching speed, and selector means for selectively connecting said manually controlled means or said inching control means in'said circuit.

l0. A press comprising a ram, means for reciprocating the ram including a rotary shaft, means for driving the shaft including an electromagnetic slip coupling, said coupling including relatively rotatable iield and inductor members, one of said coupling members being coupled to drive the shaft, said coupling field member including a eld coil, a control circuit including manually :controlled means vfor energizing said field coil to apply high torque through said coupling to said shaft to reciprocate the ram at relatively high speed, means operating in timed relation to said ram'for automatically deenergizf ing said field coil after the rain has passed midstroke, inching control means for energizing said field coil to apply low torque through said coupling to said shaft toreciprocate the ram at inching speed, and selector means for vselectively connecting said timed means in said circuit for singie-stroke operation of the ram or for shunting said timed means out of said circuit for continuous operation of the ram, said selector 4means also being operable for selectively connecting said manually controlled means or said inching control means in said circuit.

ll. In a press, a frame, aram shaft, a drive shaft, a speed-reduction connection between the drive shaft land the ram shaft, a motor-driven i'iy wheel, an inductive electric slip coupling between the fly wheel and drive shaft, an inductive electromagnetic non-friction brake operative from the frame directly on the drive shaft at drive shaft speeds, an electromechanical friction brake operative directlyY on the ram shaft at ram shaft speeds, and switching elements for automatically controlling the sequence of operations of said electric coupling, electromagnetic brake and fricti-on brake and adapted during one revolution of the ram shaft to apply and release the electric coupling short of a full revoultion, apply and release the'electric brake during said revolution, the release of the electromagnetic brake coming after release of the electric coupling and said friction brake being applied during said revolution and during the period `after the inductive coupling is released and after a substantial period of application of the electric brake.

12. In a press, a frame, a ram shaft, a drive shaft, a speed-reduction,connection between the drive shaft and the ram shaft, a motor-driven fiy wheel, an inductive electric slip kcoupling between the fl-y wheel and drive shaft, an inductive electromagnetic brake operative from the frame directly on the drive shaft at drive shaft speeds, an electromechanical friction brake operative directly on the ram shaft at ram shaft speeds, a plurality of cam-operated switch elements responsive to movement of the ram shaft and connected in an electrical network with said brakes and coupling, and a control unit for said network having a plurality of manually selective positions wherebyvin a first position said switch elements automatically control 'the sequence of operations of said electric coupling, electromagnetic brake and friction brake so that during one revolution of the ram shaft the electrical coupling is applied and released short of a full revoluticn, the electromagnetic brake is applied and released during said revolution, the release of this electromagnetic brake coming after the release of the electric coupling and said friction brake being applied during said revolution and during the period after the inductive coupling is released and `after a substantial period of application of the electromagnetic brake; and in second position only the slip coupling is normally energized; and in a third position said slip coupling is energized at a sub-normal value to apply low torque to said ram shaft to reciprocate it at inching speeds.

13. In a press, a frame, a ram shaft, a drive shaft, -a speed-reduction connection between the drive shaft and the ram shaft, a motor-driven ily wheel, an inductive electric slip coupling between the ny wheel and drive shaft, an inductive electromagnetic brake operative from the frame on the drive shaft at drive shaft speeds, an electromechanical friction brake operative directly on the ram shaft at ram shaft speeds, a plurality of cam-operated switch elements responsive to movement of the ram shaft and connected in an electrical network with said brakes and coupling, and a control unit for said network having a plurality of manually selective positions whereby in a first position said switch elements automatically determine a predetermined sequence of operations of said electric coupling, electromagnetic brake and friction brake so that during a given revolution of the ram shaft the electrical coupling is connected and later released, the electromagnetic brake is applied and released during said revolution, the release of this electromagnetic brake coming after the release of the electric coupling and said friction brake 'being applied during said revolution and during the period after the inductive coupling is released and after a substantial period of application of the electromagnetic brake; and in second position only the slip coupling is normally energized; and in a third position said slip coupling is energized at a sub-normal value to apply low torque to said ram shaft to reciprocate it at inching speeds.

1li. In control means for cyclically operating press machines, a source of power, driving means connectible to said source, operating means for the press, magnetic flux clutch means between the driving means and the operating means, a dynamic iiux brake, a mechanical solenoid brake both brakes being applicable to the operating means and switching means for controlling the clutch and brakes to energize the flux brake upon de-energization of the clutch to provide initial stoppage force then apply the solenoid brake and lastly remove the iiux brake in sequence.

15. In control means for cyclically operating machines, a motor, movable machine parts which it is desired to drive with the motor, a magnetic nux clutch between the motor and the movable parts, a mechanically biased brake means to apply braking pressure to the movable parts, solenoid means to release brake pressure, supplemental dynamic nur; brake means for the movable machine parts and control means for energizing the solenoid and flux clutch and in timed sequence the dynamic brake including relay switching 14 means in combination with cam operated switching means.

16. In a control system for a press, a source of alternating current power, a motor connectible to said power, rotatable means for driving said press, magnetic flux clutch means between the motor and the rotatable driving means, energizing coils mounted in the clutch means, dynamic flux brake means associated with the rotatable means to stop the same, a second series of energizing coils for the brake means, a solenoid released friction brake applied to the rotatable means, rectifying means connected to the power source and to the two series of coils, transformer means connected to the source and to the solenoid and switching means including both relay and cam operated switches to control the operation of the clutch and brakes.

17. In a control system for a press, a source of alternating current power, a motor connectible to said power, rotatable means for driving said press, magnetic flux clutch means between the motor and the rotatable driving means, energizing coils mounted in the clutch means, dynamic nux brake means associated with the rotatable means to stop the same, a second series of energizing coils for the brake means, a solenoid released friction brake applied to the rotatable means, rectifying means connected to the power source and to the two series of coils, transformer means connected to the source and to the solencid, switching means to cause the energization of the clutch means and the release of the friction brake to start the press, cam operated switch means to (ie-energize the clutch and sequentially energize the dynamic brake and then the friction brake to bring the press to a stop.

i8. An electric control for a power operated cyclically operating machine of the type comprising a continuously running motor for supplying power to the machine; a power transmission element rotatable idly by the motor when the machine is at rest; a magnetic clutch energizable effectively to clutch the transmission element to the machine to drive it; a magnetic brake energizable effectively to brake the machine to stop it; a friction brake for the machine biased to set condition and having electrically actuable means to release it; the control comprising a source of current; a control system energized by current from the source and comprising contacts and circuits controlled thereby which when electrically actuated cause release of the friction brake by its electrically actuable means and effective energization of the magnetic clutch; and which when rie-actuated cause discontinuance of effective energization of the magnetic clutch and cause energization of the magnetic brake effectively and allow the friction brake to set and, after a time interval, cause discontinuance of eective energization of the magnetic brake; and control contacts controlling actuation and de-actuation of the said circuits.

i9. ln a control system for a press, a source of alternating current power, a motor connectible to said power, rotatable means for driving said press, magnetic flux clutch means between the motor and the rotatable driving means, energizing coils mounted in the clutch means, dynamic iiux brake means associated with the rotatable means to stop the same, a second series of energizing coils for the brake means, rectifying means connected to said source of power, means for connecting said two series of coils in parallel across the rectiner output, and a plurality of separate switchving means operated in timed relation controlling the timed energization of said series of coils.

20. In a control system for a press, a source of alternating current power, a motor connectible to said power, rotatable means for driving said press, magnetic iiux clutch means between the motor and the rotatable driving means, energizing coils mounted in thefclutch means, dynamic iiux brake means associated with the rotatable means to stop the same, a second series of energizing coils vfor the brake means, a solenoid released friction brake applied to the rotatable means, rectifying means connected to the power source and to the two series of coils, transformer means connected to the source and to the solenoid, switching means to cause the energization of the clutch means and the deenergization of the brake means to start the press, cam operated switch means to deenergize the clutch and sequentially energize the dynamic brake and then the solenoid brake to bring the press to a stop, and safety switch means in a shunt circuit to a portion of said switching means to prevent movement of the press.

21. In a control means for a press having a movable ram, operating means for said ram, magnetic ux clutch means mounted between the operating means and the ram to drive the latter only through a magnetic field coupling, inductive means in said magnetic iiuX clutch for providing said eld, a source of power, conductive means connecting said source with the inductive means for the clutch, a solenoid friction brake mounted to bear against the operatingr means, and relay means for controlling said solenoid brake connected in the conductive connecting means to the clutch so that the brake is released when the clutch is energized.

22. 1n a control system for a cyclically operated machine such as a press, a magnetic coupling for intermittently operating-the machine, the coupling having an intermittently energized eld coil, a magnetic brake for intermittently braking the machine, the magnetic brake having an intermittently energized eld coil, a control circuit controlling the energization of the respective eld coils, switch means connected in said circuit operated in timedv relation with movement of the machine intermittently to energize and deenergize the respective iield coils during a cycle of operation, the control circuit including means connected across the respective field coils adapted to absorb inductive energy of the field coils.

23. 1n control means for cyclically operating machines, a motor, movable machine parts which it is desired to drive with the motor, a magnetic flux clutch between the motor and the movable parts, mechanical friction brake means adapted to brake the movable parts, electric control means for the mechanical friction brake, supplemental dynamic flux :brake means for the movable parts, and control means for energizing the flux clutch and the electric control means for the friction brake and in timed sequence the dynamic brake including relay switching means in combination with cam operated switching means.

24. In a control system for a press, a source of alternating power, a motor connectible to said power, rotatable means for driving said press, magnetic linx clutch means between the motor and the rotatable driving means, a rst group of energizing coils mounted in the clutch means, dynamic flux brake means associated with the rotatable means to stop the same, a second group of energizing coils for the brake means, rectifying means connectible to said source of power, means for connecting said two groups of coils across the rectifier output, and resistance means adapted to be connected at will into the control system and elective in respect to the clutch coils to reduce the current thereto.

MARTIN P. WINTI-IE-R.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 744,423 Steckel Nov. 17, 1903 817,687 Bacon Apr. 10, 1906 1,136,279 Severy Apr. 20, 1915 1,541,760 Cameron June 9, 1925 1,663,443 DArdenne Mai'. 20, 1928 1,945,282 Lindgren Jan. 30, 1934 2,085,745 Gerber July 6, 1937 2,233,060 Parvin Feb. 25, 1941 FOREIGN PATENTS Number Country Date 558,961 Great Britain Jan. 28, 1944 

